1. Field of the Invention
The present invention pertains to a gas detector system, and more particularly, pertains to a detector for the detection of gas, such as CO.sub.2, in a sample cell by a thermopile assembly where extensive thermal insulation of the component parts promotes stability of the detector and its components. A summing circuit sums four signals to derive a signal indicative of CO.sub.2 concentration in the gas.
2. Description of the Prior Art
Prior art systems were susceptible to any variation in the heater temperature which caused large variations in the detector output. If the heater temperature changes, there is less or more infrared energy. The detector measures this as a change in the amount of CO.sub.2 in the gas chamber, so monitoring the heater temperature is very critical and this was not previously done.
Prior art systems have also used comparative techniques of a chopper wheel with moving mechanical components to switch from a known CO.sub.2 cell to an unknown CO.sub.2 cell, and then derive the concentration by the different readings between the two cells.
The present invention overcomes the disadvantages of the prior art by providing a gas detector system which has thermal stability and is not effected by ambient changes, a lower wattage heater source, and a lower circuit gain, thereby minimizing noise in the system.